In some cases, a surge current caused by lighting or the like flows in a communication device including a telephone or the like. If the surge current flows in the communication device, the communication device may be broken or an operation failure may occur. Therefore, a discharge element (also referred to as a surge absorber) for letting the surge current out by electric discharge is mounted on the communication device for protection from the surge current.
A gap-type discharge element that is one type of the discharge element causes a discharge current to flow through a spark gap when a surge current flows therein. Therefore, the surge current flows via the discharge element, so that it becomes possible to prevent the surge current from flowing into the communication device.
A discharge element disclosed in Patent Literature 1 as the discharge element of the above type is structured such that a substrate with a plurality of conductive thin films spaced apart by a spark gap of a predetermined size is placed inside a glass tube whose both ends are air-tightly sealed by melting. Two leads with terminals are introduced into the glass tube and the terminals are connected to the respective conductive thin films located at both ends. The inside of the glass tube is filled with a gas for adjusting the discharge voltage.